I have just purchased Disco 3, its a 54 plate with 61k on the clock, it has full LR service history and many new parts, it seems that little expense was spared by the previous owner.. I know the timing belt should have been replaced at 7 years or 105k miles, this is one thing that appears not to have been done, so I need to get it sorted. I have seen that suppliers sell a kit with an oil pump as part of the kit, is this something that I need to get replaced at the same time as the timing belt?

I would almost go as far as to say, drive it as little (not at all!) until the timing belt is done. Every 7 years it should be done - so 2013 - it might well be it was done, in which case its coming up to it again anyway.

I would change the pump too - they don't generally go on that age vehicle - but they can and do - @Stu can vouch for that one! @Bodsy has had 2 engine failures at least one was oil pump but a newer model

And anyway even though its only done low miles, it is still the beating heart of the engine!

And make sure the pump is stamped FOCO (Or whatever the mnemonic is as that doesn't look right!